javascript variable declaration rules code example

Example 1: javascript variable

var user_name = prompt("Please enter your name:", "Type here");
alert("Hello " + user_name);

Example 2: how to define variable in javascript

var <variable-name>;

var <variable-name> = <value>;

Example 3: how to declare variables javascript

//variables are a way to easily store data in javascript
//variables are declared by the var keyword, example...
var x = 10;
//or
var dog_name = "daisy";
//which can also be written as 
var dog_name = 'daisy';
//same thing with single quotes and double quotes

Example 4: javascript variable declaration

var name = "mamama";
document.write(name);
// Outputs "mamama"

Example 5: javascript variables

// Also let, const
var e_number = 0;
var e_string = '';
var e_true = true;
var e_false = false;
var e_undefined = undefined;